The subject invention relates to paperboard containers, and specifically to paperboard cartons having opening members defined by perforations. As an example, the subject invention may be used in boxes to store and dispense facial tissues. Of course, as will be evidenced from the following description, the subject invention is not so limited, and can be incorporated into any paperboard structure having an opening member defined by perforations.
Generally, the area of the paperboard container to be opened is outlined by an array of perforations. More particularly, each perforation comprises a single die-cut which extends entirely through the paperboard material. The individual die-cuts typically are separated from one another by relatively short sections of continuous, non-cut paperboard material which function to keep the opening member engaged to the remainder of the container prior to opening. These continuous sections must be strong enough to keep the opening member and the remainder of the container intact during packaging, shipping and storage. However, the array of perforations must be such that the opening member can be easily and precisely separated from the remainder of the container by the user.
The opening member typically includes a starting point or tab at which the user of the container initially exerts a force to separate the opening member from the remainder of the container. In many paperboard containers, the starting point will define a pull tab. Beginning at this starting point, the user exerts a force in an appropriate direction so as to tear the continuous sections intermediate adjacent perforations. The array of perforations on the container is such that the continuous sections intermediate adjacent perforations will tear in a predictable manner, thus effecting the desired separation of the opening member from the remainder of the container.
Paperboard containers made according to known designs include many distinct arrangements of perforations. However, in many prior art containers, the sections which are torn between two adjacent perforations define ragged edges. Additionally, the tearing action often will cause fibers of the paperboard material from which the prior art containers are constructed to become separated from the body of paperboard material. Furthermore, the tearing action frequently causes delamination of certain layered paperboard structures and can cause unintended tears outside the area defined by the array of perforations. The ragged edges resulting in opening many prior art paperboard containers often make the removal of material from the paperboard container difficult. In particular, in prior art paperboard containers used for storing facial tissues or other products made from thin sheets of fragile material, the ragged edges are known to catch the stored items as they are being removed from the container. This can result in a tearing of the tissues, or other similar material stored in the prior art paperboard container. The disengaged fibers of paperboard material that often are generated in opening many prior art paperboard containers frequently present an undesirable aesthetic or hygenic condition. For example, the user of facial tissues generally would find slivers of fibrous paperboard material aesthetically undesirable if not unacceptable. Similarly, these slivers of material may be hygenically unacceptable on prior art paperboard containers used with food products.
U.S. Letters Pat. No. 4,212,395, entitled MULTI-ANGLED PERFORATED OPENING DEVICE which issued to Ralph J. Korte on July 15, 1980 and which is assigned to the assignee of the subject application is directed to an improved arrangement of perforations in a paperboard container which substantially reduces the degree to which the torn edges of a perforated opening remain ragged, and similarly, reduces the likelihood of fibrous members being separated at the torn edges. The disclosure of U.S. Pat. No. 4,212,395 is incorporated herein by reference. Specifically, the perforations which define the opening member in the paperboard container of U.S. Pat. No. 4,212,395 form a symmetrical curvilinear outline. This curvilinear outline comprises a plurality of associated pairs of arcuate segments, with the segments of each pair being disposed in a mirror image arrangement on opposite sides of the axis of symmetry. All of the perforations of a segment are disposed at substantially the same predetermined angle with respect to the axis of symmetry of the outline. However, the perforations of one segment are disposed in a different angle with respect to that axis than the perforations of at least one of the segments immediately adjacent thereto. Additionally, the perforations of each segment of an associated pair of segments is disposed at an angle relative to the axis of symmetry which is the mirror image of the angle of the perforations of the other segment of the associated pair. This arrangement, as explained in U.S. Pat. No. 4,212,395 provides ease of tearing plus strength against accidental collapse during packing, handling, shipping, or storing of the paperboard container. Furthermore, the arrangement of perforations in the paperboard container of U.S. Pat. No. 4,212,395 reduces the raggedness of the torn edges and minimizes the degree to which fibrous material will become separated from the torn edges of the container. Reference is made to U.S. Letters Pat. No. 4,218,497 entitled "METHOD FOR DIE CUTTING A PLASTIC WEB" and assigned to the assignee of the subject invention. In U.S. Letters Pat. No. 4,218,497 a frangible but non-splintering coating is applied to a web to prevent hair-like slivers on a cut edge.
The multi-angled perforated opening disclosed in the paperboard container of U.S. Pat. No. 4,212 395 has been found to be extremely desirable and effective. However, it has been found desirable to develop a paperboard container with a perforated opening having even further improvements.
Accordingly, it is an object of the subject invention to provide a paperboard container having an opening member defined by an array of perforations such that the edges formed by the tears between adjacent perforations when the container is opened will be less ragged than in known containers.
It is another object of the subject invention to provide a paperboard container having an opening member defined by an array of perforations that will further reduce the possibility of fibrous material becoming separated from the paperboard material as the paperboard container is being opened.
It is a further object of the subject invention to provide a paperboard container having an opening member that will minimize the possibility of inadvertent tears of the paperboard material while the subject paperboard container is being opened.
It is still an additional object of the subject invention to provide paperboard containers with an array of perforations defining an opening member and with a strip of coating material to inhibit uneven tearing of the paperboard sections between adjacent perforations.